|Attacks by Boko Haram have killed hundreds, mostly in the majority Muslim north [EPA]
The Nigerian Islamist group Boko Haram has ended all negotiations with the authorities, saying it could not trust a government of "unbelievers".
A spokesman for the group on Tuesday said it had "closed all possible doors of negotiation" with the government and called on Muslims to join the fight against it.
The statement to local journalists in Maiduguri came two days after a Muslim cleric brokering initial peace talks pulled out, casting shadows over an already dimmed situation.
"Almighty God has told us repeatedly that the unbelievers will never respect the promises they made. As such, henceforth, we will never respect any proposal for dialogue," Abu Qaqa, a Boko Haram spokesman, said by phone in the northern Hausa language.
The departure of Datti Ahmed, a former ally of Boko Haram's founder, could be a major blow for talks which were only in their early stages, although some security sources doubt peace talks are possible with a sect so fragmented and radicalised.
'Restoring the Caliphate'
The negotiations were aimed at ending months of bomb and gun attacks by Boko Haram that killed hundreds, mostly in the majority Muslim north, and have at times dominated Goodluck Jonathan's presidency.
The group has said it wants to impose Islamic sharia law across the oil-rich country split equally between Christians and Muslims.
"We are certain we will dismantle this government and establish Islamic government in Nigeria," Abu Qaqa said.
"There is no doubt in our minds we will emerge victorious.
"We are calling on all Muslims in this part of the world to accept the clarion call and fight for the restoration of the Caliphate."
However, recent arrests and deaths of senior figures have weakened the group, analysts say.
It has not managed to launch a widescale, co-ordinated attack since one in Kano that killed 186 people in January, reverting to crude bomb attacks and drive-by shootings.